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31.
Circadian variations in the activities of aldehyde dehydrogenase (ALDH) isozymes in the subcellular fractions of the brain and liver were investigated in male and female mice of C57BL/6J strain. The rhythms in high Km-ALDH activities of brain and liver mitochondrial fractions which existed in ordinary light-dark cycle were not observed in animals maintained in the continuous darkness for two weeks. The rhythms in high Km-ALDH activities of hepatic soluble and microsomal fractions existed in both ordinary cycle and total darkness but the rhythmic phases were different. In the low Km-ALDH activity of hepatic mitochondrial fraction, the circadian rhythm was similar in two lighting conditions. There was sex difference in the existence of the circadian rhythm. It seems that the ALDH activity of mice is influenced by light-dark cycle and sex hormones. 相似文献
32.
Calcium-sensitive cls4 mutant of Saccharomyces cerevisiae with a defect in bud formation. 总被引:19,自引:2,他引:17 下载免费PDF全文
A calcium-sensitive cls4 mutant of Saccharomyces cerevisiae ceased dividing in the presence of 100 mM CaCl2, producing large, round, unbudded cells. Since its DNA replication and nuclear division still continued after interruption of normal budding, the cls4 mutant had a defect in bud formation in Ca2+-rich medium. Its calcium content and calcium uptake activity were the same as those of the wild-type strain, suggesting that the primary defect of the mutation was not in a Ca2+ transport system. Genetic analysis showed that the cls4 mutation did not complement the cdc24-1 mutation, which is known to be a temperature-sensitive mutation affecting bud formation and localized cell surface growth at a restrictive temperature. Moreover, cls4 was tightly linked to cdc24, and a yeast 3.4-kilobase-pair DNA fragment carrying both the CLS4 and CDC24 genes was obtained. These results suggest that the cls4 mutation is allelic to the cdc24 mutation. Thus, Ca2+ ion seems to control bud formation and bud-localized cell surface growth. 相似文献
33.
Cloning and expression of human lymphotoxin mRNA derived from a human T cell hybridoma 总被引:2,自引:0,他引:2
We cloned human lymphotoxin (LT) cDNA from a cDNA library prepared from phorbol myristate acetate (PMA) and Con A-stimulated human T cell hybridoma (AC5-8) cells, The nucleotide sequence of the cDNA insert in the plasmid, pLT13, was determined and compared with those of peripheral blood mononuclear cell derived LT cDNA and the LT gene. Four stretches, containing 14 nucleotides in total, were different among the three sequences. The differences included one base change from C to A in the coding region. Because this change was expected to result in a change in the amino acid at position 26 from Thr to Asn, we constructed an E. coli expression plasmid (pLT13tac6-8.2) and a mammalian cell expression plasmid (pSV2-LT) in order to confirm that pLT13 contains the coding sequence of human LT. Both plasmids were found to synthesize active LT molecules after transfection into JM105 and COS-1 cells, respectively, and their lytic activities were found to be completely neutralized by anti human LT serum. Using an insertion mutant and a deletion mutant, we examined the role of the C terminal domain in the LT activity. The results obtained strongly suggested that the intactness of the C terminal less than 10 residues is required for the LT activity. 相似文献
34.
Proton gradient-coupled uphill transport of glycylsarcosine in rabbit renal brush-border membrane vesicles 总被引:4,自引:0,他引:4
Y Miyamoto V Ganapathy F H Leibach 《Biochemical and biophysical research communications》1985,132(3):946-953
An inward-directed proton gradient energizes the transport of intact glycylsarcosine against a concentration gradient in rabbit renal brush-border membrane vesicles. Dissipation of the proton gradient abolishes the uphill transport. Generation of an inside-negative membrane potential nearly doubles the intravesicular concentration of the dipeptide at the peak of the overshoot without altering the equilibrium value. These data provide direct evidence for peptide-proton cotransport in the renal brush-border membrane. 相似文献
35.
Isolation of porcine follicular fluid inhibin of 32K daltons 总被引:17,自引:0,他引:17
K Miyamoto Y Hasegawa M Fukuda M Nomura M Igarashi K Kangawa H Matsuo 《Biochemical and biophysical research communications》1985,129(2):396-403
Purification of ovarian inhibin from porcine follicular fluid was performed by using an bioassay based upon the suppression of spontaneous FSH release from cultured cells of rat anterior pituitary. The presence in the follicular fluid of four molecular forms of inhibin activity corresponding to Mr 100K, 80K, 55K and 32K was revealed by SDS-gel electrophoresis under non-reducing conditions. The smallest inhibin amongst them, named 32K inhibin, eliciting about 70% of the total activity in the follicular fluid, was separated by gel filtration in the presence of 8 M urea. By subsequent ion-exchange chromatography, followed by RP-HPLC, 32K inhibin was purified to homogeneity with a 8,000 fold purification factor in a yield of 12%. The purified 32K inhibin was found to comprise two polypeptide subunits (Mr 20K and 13K), linked by disulfide bridges and to specifically suppress the secretion of FSH, but not of LH from the pituitary cells. 相似文献
36.
Developmental changes in components of chick brain microtubule-associated protein-1 (MAP-1) and tau proteins 总被引:1,自引:0,他引:1
Microtubule proteins were purified from chick brains at various developmental stages from the 12-day embryo to adult. Three species of microtubule-associated protein-1 (MAP-1) and 5-7 molecular components of tau proteins were observed by SDS-polyacrylamide gel electrophoresis. The molecular compositions were observed to change during development of the chick brain. 相似文献
37.
Arterial perfusion of frog tongue for intracellular recording of taste cell receptor potential 总被引:1,自引:0,他引:1
Y Okada T Miyamoto T Sato 《Comparative biochemistry and physiology. A, Comparative physiology》1985,81(2):247-250
The frog tongue was perfused through its artery with a Ringer solution using a peristaltic pump, and a method was developed to record stable intracellular receptor potentials of taste cells. Perfusing at 0.05 ml/min with a Ringer solution containing 5% dextran did not cause tongue edema, but perfusing at the same rate with Ringer without dextran caused edema. After perfusion at 0.05 ml/min with 100 mM K Ringer, the membrane potential of taste cells gradually decreased and reached a constant level in about 30 min, indicating that the intercellular fluid of the tongue could be replaced within this time period. While the artery of the frog tongue was perfused at 0.05 ml/min with Ringer containing 5% dextran, intracellular receptor potentials of taste cells elicited by four basic taste stimuli (1 M NaCl, 10 mM quinine-HCl (Q-HCl), 1 mM acetic acid and 1 M galactose) were similar to those obtained from the control taste cells under normal blood flow. 相似文献
38.
Production of human c-myc protein in insect cells infected with a baculovirus expression vector. 总被引:30,自引:3,他引:27 下载免费PDF全文
C Miyamoto G E Smith J Farrell-Towt R Chizzonite M D Summers G Ju 《Molecular and cellular biology》1985,5(10):2860-2865
A cDNA fragment coding for human c-myc was inserted into the genome of the baculovirus Autographa californica nuclear polyhedrosis virus adjacent to the strong polyhedrin promoter. Insect cells infected with the recombinant virus produced significant amounts of c-myc protein, which constituted the major phosphoprotein component in these cells. By immunoprecipitation and immunoblot analysis, two proteins of 61 and 64 kilodaltons were detected with c-myc-specific antisera. The insect-derived proteins were compared with recombinant human c-myc-encoded proteins synthesized in Escherichia coli and Saccharomyces cerevisiae cells. The c-myc gene product was found predominantly in the nucleus by subcellular fractionation of infected insect cells. 相似文献
39.
T Ikehara H Yamaguchi K Hosokawa M Kaku H Miyamoto 《Journal of cellular biochemistry》1985,28(4):273-280
phenazine methosulfate (PMS) stimulates ouabain-sensitive Rb+ uptake by HeLa cells. This stimulation cannot be attributed to the effect of the dye on the intracellular Na+ or ATP content. Respiratory inhibitors, such as 5 mM NaCN and 5 microM rotenone, and anaerobic conditions enhance the stimulation of Rb+ uptake by PMS. Cellular respiration is stimulated, but lactate production is reduced in the presence of PMS, irrespective of the presence of respiratory inhibitors. Cellular NADH is oxidized markedly on addition of PMS plus inhibitors, but it is not affected by addition of the inhibitors only. In the presence of a high concentration of PMS, PMS-stimulated ouabain-sensitive Rb+ uptake is inhibited by addition of ascorbate. From these results it is concluded that Na+K-pump activity is closely related to the cellular redox state. 相似文献
40.
A Ca2+, calmodulin-dependent protein kinase from rat brain with a MW of 640,000 phosphorylated calmodulin-sensitive phosphodiesterase from the brain cytosol. The Km of the enzyme for the phosphodiesterase was 5.0 microM and the Vmax was 212 nmol/mg/min. The amount of phosphate incorporated into the phosphodiesterase was 0.7 mol/mol subunit. Phosphorylation of the phosphodiesterase enhanced the enzyme activity by about 20% for hydrolysis of a higher concentration of cyclic AMP. 相似文献